I bought a new iMac and went crazy with Faces in iPhoto. Two days later I had a lot of tagged photos in Faces. Then I noticed that since I synced my Address Book with Google Contacts, Address Book entries were appearing as suggestions in Faces.

I didn't want to re-tag all my existing Faces photos, but there didn't seem to be an obvious way to link a new Address Book contact to an existing Face. So I took the only honorable course of action and starting messing around.

I discovered that you can transfer a Faces collection to an Address Book contact very quickly.

Assume you're working on John in your Faces collection, who has the entry John Doe in your Address Book. Go into Faces and pick any photo of him, double-click to view it and then click name. Start retyping John and John Doe should be one of the suggested values, with an Address Book icon next to the name. Click to select it.

Go back to the Faces cork board and you should now have your original John collection and your new John Doe collection. Drag the John icon and drop it on John Doe - job done. The two will merge and you'll only have the one John Doe to worry about. Name and email address are imported from Address Book into iPhoto, but as far as I can tell, Address Book doesn't gain a photo icon automatically.

It won't mean much to you if you did the sensible thing and set your Address Book up first, but discovering this technique spared me from the ghastly task of starting thousands of Faces tags again from scratch.

I remember that you can just retype the name in the Faces cork board. Address Book entries will appear as you type, and you can select from the list. Can't try it myself as my iPhoto entries already tie will Address Book.

What I would like to do is somehow be able to change the default photo that is "on top" of the Faces stack. As I understand it it defaults to the first picture 'named" which is _often_ not the most ideal...